The invention disclosed herein relates to electronically charged fuzes capable of multiple explosive outputs.
Conventional (nonnuclear) weapons with high-explosive warheads generally employ solid explosive fillers which are initiated from within the warhead by a fuze which is a integral part of the warhead. The detonation takes place at a specific position or time, either above, on, or in the target. Usually, the small variations from a desired position or time are not crucial to effectiveness, nor are they factors in the detonation of the high explosives. Large variations may produce reduced effectiveness but still do not produce duds.
The advent of fuel-air explosive (FAE) warheads has challenged ordnance designers to create fuzes which produce more than one explosive output to control warhead-to-target approach speed, orientation, and height-above target for proper fuel dissemination and aerosol cloud formation. Additionally, a detonation shock must be provided to the resultant fuel-air cloud at the correct time and in the proper position to cause it to detonate; otherwise, the cloud will simply deflagrate or fail to iginite, both of which outcomes are ineffectual.
Accordingly, it is the primary object of this invention to provide an ordnance fuze for a rocket-propelled fuel-air explosive round, which provides three consecutive separate detonation outputs. The first is during the round's flight at an accurate and remotely presettable time (setting is accomplished when the round is in its launcher) to control the round's range; the second is when the warhead of the launched round is six feet from striking its target terrain; and the third is at a precise short time interval after the second. This will replace three separate and complexly interconnected fuzes known on the prior art. The prior art method of accomplishing the objective of providing three outputs necessitates three separate ordnance fuzes for the round which are interconnected on the round by mechanical and explosive means. The first fuze, the FMU-83/B mechanical time fuze, provides an explosive output at a variable presettable time. In order to accomplish this, the fuze timer must be set by hand before the round is installed in its launch tube because there is no fuze access with the round in its tube. A change in mission time necessitates removal of the round from the tube to reset the timer. The FMU-83/B requires an arming wire to secure the fuze from timing before launch. At launch, the fuze disengages from the wire. Routing of the wire through the launcher and, attachment to the launcher is clumsy and unreliable. The functioning of this fuze, in addition to its primary purpose of explosively initiating the deployment of a parachute, causes a cover to be explosively expelled from the second fuze (an FMU-95/B bomb fuze) and provides a piezoelectrically generated electrical input to that fuze, and releases the catch on the third fuze to allow it to move into explosive transfer alignment with the output charge of the second fuze. The second fuze then operates to deploy a four-foot extendible probe, after a mechanically timed delay, to provide firing standoff between the round and the target terrain. At terrain contact, the probe tip causes a stab detonator to fire and stress a piezoelectric crystal which, in turn, generates voltage to fire an electric detonator. The output of the electric detonator is fed to the third fuzing device, which initiates expulsion of certain detonating devices from the round and, by means of a pyrotechnic delay element in its explosive train, also initiates the round's main charge at a short and imprecise time interval later for fuel dissemination and cloud formation.
The disadvantages of the prior art fuzes are as follows:
a. The first fuze setting cannot be changed once the round is in the launcher, significantly curtailing system flexibility.
b. Three fuzes are employed, which is expensive, due to redundancy of housings, arming devices, and associated explosive components.
c. An external interconnection mechanical and explosive network must be provided the three fuzes.
d. An arming wire must be provided to initiate the first fuze. This requires in-the-field attachment to the launcher, which increases launch preparation time and may not always be reliably achieved under combat-stress conditions.
e. The extendible probe provides only four feet of standoff where six feet are required to obtain optimum cloud thickness.
f. The pyrotechnic delay for fuel dissemination varies extensively with temperature, adversely affecting the round's performance.
g. The second fuze has a two-minute delay pyrotechnic self-destruct mechanism which operates in the event the fuze does not fire at terrain impact. This device is expensive and unreliable.
Therefore, with the background of the invention set forth above, some of the objects, in addition to the primary object set forth above are as follows:
It is one additional object of the invention to provide an electronically chargeable fuze that can be remotely set or reset in a very short period of time.
It is also one object of the invention to provide a fuze with a rotatable rotor where the rotor has at least three detonator ports, with a detonator positioned in each port and where each detonator is oriented to point in a direction different from each adjacent detonator.
It is another object of this invention to provide a single electronically chargeable fuze that has the minimum number of components necessary to accomplish three explosive outputs.
It is one additional object of this invention to provide a fuze that is capable of close tolerance timing for the first and third detonations.
It is a still further object of the invention to provide a fuze with a simple, inexpensive redundant inertia switch electrically parallel to the probe switch that initiates the second and third detonations despite the failure of the probe to function properly, in order to detonate otherwise unexploded explosives and thus preclude enemy usage of such material against our own forces.
It is another object of this invention to replace a pyrotechnic self-destruct mechanism with an inertia switch which is electrically in parallel with the probe switch so that if the probe switch fails to close, the inertia switch will function on round impact thus causing the remaining explosives (cloud detonators and burster charge) to detonate and thereby eliminate residual or undetonated explosives in the event of a dud round.
It is another object of this invention to provide a fuze with electrical inertia switch means to provide an automatic clean up or self destruction of residual explosives.